The present invention relates generally to flow control, and in particular to flow control and diverter valves for fluid processing. In specific embodiments, the invention concerns a rotary cylinder valve that operates as a dual diverter valve for chemical removal systems such as an amine-based carbon dioxide (CO2) and water (H2O) removal system.
Environmental control and life support systems (ECLSS) are a critical aspect of human spaceflight. The prohibitive cost of delivering consumables into space makes it imperative that these systems utilize recirculation, particularly for high-volume consumables like water and air. Recirculating air revitalization and CO2 removal systems are thus an integral part of ECLSS technology, including ECLSS applications for the space shuttle, the international space station, and future missions slated for the Orion crew vehicle or other advanced spaceflight systems.
Carbon dioxide removal is essential to ECLSS, because CO2 helps regulate the breathing mechanism. Any increase above a few tenths of a percent CO2 by volume can cause headaches and nausea, while “foul air” conditions (where CO2 concentrations exceed a percent) can ultimately be fatal. Typical CO2 removal systems employ active amine adsorption sites (usually distributed in amine “beds”), which remove metabolic CO2 from air as it recirculates through the crew cabin, crew quarters, or even individual spacesuits. This process is similar to amine-based gas “sweetener” systems, which remove CO2, hydrogen sulfide (H2S) and other sour-smelling gases from oil refinery, petrochemical, and natural gas processing streams.
CO2 removal for ECLSS requires precision flow control and fail-safe valve assemblies, incorporated into small, lightweight packages with simple, reliable designs that meet the rigorous demands of aerospace applications. There is an ongoing need for valves that address these issues, and, ideally, are further adaptable to collective protection systems that guard against chemical, biological, and nuclear agents, and to other, more generalized fluid processing applications.